The ultrafast lasing dynamics of single zinc oxide (ZnO) nanotetrapods and nanowires are investigated by two-color femtosecond excitation/optical injection spectroscopy. The optical gain spectra obtained as a function of time and wavelength provide a means to distinguish the lasing from other emissions and are thus used to investigate the wavelength-dependent lasing dynamics in nanowires.

One-dimensional (1-D) ZnO nanostructure arrays, such as nanowires, nanonails and nanotrees, are synthesized by oxygen assisted thermal evaporation of metallic zinc on a quartz substrate over a large area. The optical and electrical properties of the ZnO nanowire and nanonail arrays and also the applicability of these ZnO 1-D nanoform arrays as gas sensors are investigated.